Analysis of Damage of Joints in CRTSII Slab Track under Temperature and Vehicle Loads

Damage in joints has a significant effect on the integrity and stability of the China Railway Track System (CRTS)II slab track. In this study, a three-dimensional finite element model was established to investigate the damage law of joints in the CRTSII slab track under temperature and vehicle loads. In the finite element model, the non-linear constitutive law and damage parameter of the interface between the slabs and the cement asphalt (CA) mortar layer were defined by a cohesive zone model. Based on the limited results in this analysis, the recommendations of joint damage repair were put forward. Results show that in the formation of joint damage in CRTSII slab track, the temperature load plays a more important role compared with the vehicle load. The more the concrete loss at the narrow joint, the lower the temperature rise at which concrete stress reaches its compressive strength. If concrete loss at the bottom of the narrow joint is no more than 10%, the damaged joint can be repaired at the time when the temperature of slabs is close to the construction temperature. If concrete loss at the bottom of the narrow joint is larger than 10%, repair strategy should be taken according to the time when the joint damage is detected. During repair, improving bond strength of the interface between the slabs and the CA mortar layer and strength of joint concrete can help to prevent the repaired joint from being damaged again.